Acute effects of amperozide and paroxetine on social cohesion in male conspecifics.

The effects of acute administration of the selective 5-hydroxytrypamine (5-HT; serotonin) uptake inhibitor, paroxetine, and the potent 5-HT(2A) receptor antagonist, N-ethyl-4-[4',4'-bis(rho-flourophenyl)butyl]-1-piperazinecarboxamide (amperozide) on social cohesion was determined by using a tether paradigm, in which the movement of one of a pair of rats was restricted to one-half of an observation chamber. Administration of 0.1mg/kg paroxetine, 1.0, 3.0, and 5.0mg/kg amperozide but neither 1.0 nor 10.0mg/kg paroxetine increased time spent in contact with the untreated, tethered rat. Whereas only the lowest dose of paroxetine (0.1mg/kg) promoted social cohesion, all doses of amperozide (1.0, 3.0, and 5.0mg/kg) promoted social cohesion. The amperozide-induced increases in time spent in contact were greater than the paroxetine-induced increases in seconds spent in contact, regardless of dose. Acute administration of amperozide is more effective than acute administration of paroxetine in promoting social cohesion between pairs of male conspecifics. Amperozide may be an effective alternative treatment for patients with social anxiety disorder suffering from adverse side effects of paroxetine. Amperozide may prove to be a more effective treatment for social anxiety disorder than paroxetine, which is supported by our results.